It is known that elliptical traction or drive mechanisms are being used to an increasing extent in velocipedes of the bicycle and/or tricycle type due to the fact that they offer countless advantages for users, insofar as they promote performance of low impact exercise in addition to allowing participation of different muscle groups through simulation of walking and/or running movements.
Inclusion of elliptical traction mechanisms in bicycles and/or tricycles eliminates installation of seats, insofar as users operate these velocipedes in a standing position.
Basically, these velocipedes with driving power provided by an elliptical mechanism, in addition to possessing a basic structure consisting of a structural framework and at least two wheels, one in the front and another in the rear, include a mechanism consisting of a pair of support platforms for the user's feet installed on tubular extensions that can extend from the end portions of a bicycle's and/or tricycle's crankset. Hence, the alternating movement of the platforms between raised and lowered positions for each supporting platform produces forward movement of the velocipede.
Nevertheless, installing an elliptical mechanism usually requires alteration of a bicycle's and/or tricycle's structural framework, principally in relation to positioning of the ratchet mechanism, the fork, and the handlebars, in addition to altering the composition of basic components, hindering completion of possible maintenance procedures using replacement parts.
As an example, the elliptical bicycle designated as “Elliptigo” (United States) possesses an elongated, undulated structural frame where the fork for the front wheel, the handlebars, the rear wheel, and the drive mechanism are installed, with the drive mechanism consisting, in turn, of a pair of platforms mounted on tubular extensions that continue until they reach the crankset extensions, which are installed on a stationary sprocket mounted on a transverse shaft located on the rear portion of the bicycle's structural frame. This sprocket is outfitted with a chain that produces movement of the rear wheel so as to drive the bicycle forward.
Another elliptical bicycle model known as a “Streetstrider” (United States) includes a pair of supporting platforms for the user's feet that are installed on lengthwise tubes mounted parallel to the structural frame, with each end portion of each lengthwise tube connecting to a crankset situated on the sprocket shaft. The opposite end of each lengthwise tube is connected to an arm extending perpendicularly and continuing through a crosswise tubular guide rod member to support the handlebars, with the free ends of each arm containing the respective brake levers and handles.
Although the previously described elliptical bicycle models promote performance of elliptical exercises, these models are characterized by complex structural features that tend to increase the cost of velocipedes, in addition to making possible repairs difficult.